1. Field of the Invention
This invention relates to antennas, specifically to a connection scheme for antenna elements, such as a global positioning satellite antenna, and more particularly to a dual connector assembly combining two connector types in a single package for an antenna, with a first connector having an inner conductor support and capable of providing a constant impedance connection for the signal path, including when the mating portions of the first connector are only partially engaged, and a second connector which provides for a common connection to a cable or directly to electronic equipment.
2. Description of Related Art
Connectors link the various conductors of electronic components and transmission lines to equipment or other cables. Typically, antenna components are fabricated with wire connections, and do not include their own connectors. In order to mate a high frequency application antenna to other electrical equipment, such as a receiver or transmitter, it is necessary to combine the antenna with a desired connector interface. The connector will generally be of a type that is compatible with either the mating equipment connector or a mating cable connector. For high frequency and/or field serviceable and/or configurable applications a coaxial connection is preferred. For example, a GeoHelix® GPS antenna made by Sarantel of Wellingborough, England, is available with two exposed wires for connection. It is not uncommon for antennas to terminate with wires, so that the designer may choose the appropriate connection scheme that works best for the application.
Generally, it is desirable to attach a coaxial compatible connector to an antenna device such as the GeoHelix® GPS antenna in the form of a BNC-type connector, TNC-type connector, subminiature version A (SMA) type connector, N-type connector, or the like. However, the attachment to these connectors alone does not relieve the connected design from impedance mismatches, mechanical stress, vibration, or shock.
A coaxial connector provides an electrical conductive contact between conductors of electricity having an inner conductor and an outer conductor, which is generally separated by a dielectric spacer. The connection is typically of a type that may be readily connected and disconnected, repeatedly by attachment and detachment of contact supporting structure on each conductor. The connectors usually include a small projecting male center conductor and a corresponding female center conductor made to mechanically and electrically receive the male portion. However, the center conductor portion of the connector is quite fragile and prone to damage. The center conductor portion can become damaged when, for example, the connector is misaligned during a connection. This is likely to happen during “blind-mate” connections, remotely located connections, and quick connect/disconnect applications. Generally, the center conductor is made of a bendable copper wire of finite diameter, having little or no mechanical support to resist bending or other forces. In typical coaxial connectors, the male portion of the center conductor projects and extends out beyond the outer conductor for insertion into the female portion. Thus, the center conductor tip of a coaxial cable connector is exposed and vulnerable to handling and deforming during insertion.
One difficulty with directly mounting connectors to antenna assemblies is that conventional connectors are rigid, which may result in alignment difficulties and undesirable stresses on the antenna components and circuitry. Mounting tolerances can add up to the point where proper connection is not possible, or an undesirable built-in stress applied to solder joints or the brittle antenna element results. Even if the connectors can be mounted accurately to their respective antenna assemblies, it can be difficult to get the connectors to mate. Conventional single piece coaxial connectors that are rigidly soldered are not well suited to this type of application. The problem is compounded where the connectors are positioned in a manner where they cannot be seen and must be mated blind.
In the case of sensitive, high frequency electronic components, such as brittle, fragile ceramic antennas, the connector design must also promote mechanical shock and vibration protection, and anticipate thermal expansion and contraction conditions that can stress the electronic device and soldered connections to the device. Importantly, the connector must also exhibit an impedance match with the antenna. Otherwise, signal disruption and reflections will degrade the signal quality and amplitude due to the impedance mismatch. This is especially true in the higher frequency regimes, in applications where the signal frequency is on the order of 1 giga Hertz and higher, such as global positioning satellite communications.
Although the prior art has attempted in numerous ways to minimize the impedance mismatches that normally occur in connectors, there is no teaching or suggestion to strengthen the bendable center conductor or provide any form of structural support to the center conductor while keeping the impedance constant throughout the connector engagement. Additionally, the prior art has not considered a packaged connector design capable of relieving the impedance mismatches and attenuating mechanical shock and vibration effects on sensitive electronic devices such as global positioning satellite antennas, while simultaneously providing an industry common connector for attachment to cabling and other circuitry.